New research shows second-hand smoke is just about as bad as smoking itself -- but only 24 states have banned smoking in bars and restaurants.
To keep healthy, what should employees in smoke-filled environments do?
Mayo Clinic's medical school.
"There's no lower limit of exposure to second-hand smoke that is safe," Hurt said. Even workplaces with state-of-the-art ventilation systems don't protect employees if smoking is going on inside the building, he said.
According to the American Cancer Society, 24 states have instituted a ban on smoking in bars and restaurants, while 31 ban it in private workplaces, says the Action on Smoking and Health, a nonsmokers' rights organization. A number of remaining states are considering bans on smoking in indoor public places.
Second-hand smoke has long been known to harm the heart and contribute to respiratory illnesses, but a recent study in the British Medical Journal found that exposure to second-hand smoke may increase a nonsmoker's risk of cognitive impairment and dementia -- in some cases by up to 30 percent.
High levels of exposure to second-hand smoke may also be close to actual smoking in terms of increased risk of lung cancer, diabetes and other tobacco-related maladies, according to the BMJ study.